Strategy: The Vikings offense is built around the talents of Adrian Peterson, who is inarguably the NFL's best running back. They put the ball in his hands as much as possible, and they might trot out their fullback and heavy sets more than any team in the league. The Vikings used just one wide receiver on a handful of plays and even had a few where they used none. When the Chicago Bears loaded up to stop Peterson, the Vikings had success using play-action and two-man routes to move the ball through the air. Defensively, the Vikings run a 4-3. Against the Bears, they wanted to keep two deep safeties to defend the pass, but they didn’t stop the run well enough to stick with that.

Personnel: The Vikings are a team without a clear-cut quarterback. Christian Ponder had been the starter, but he suffered a concussion Sunday and was replaced by Matt Cassel, who played better. It’s unclear which one the Ravens will face this weekend. Whoever is behind center does not have much to work with. Greg Jennings, who clicked with Cassel, is no longer a top-flight receiver and first-round pick Cordarrelle Patterson is a big-play threat but not yet a complete receiver. Defensive Jared Allen had a sack against the Bears and is always a handful. The Vikings secondary is a mess. First-round pick Xavier Rhodes has some talent, but fellow cornerback Chris Cook is vulnerable and the rest of that unit is filled with no-names.

What went right: With fullback Jerome Felton and a physical offensive line giving Peterson room to get going, Peterson carried the Vikings to a victory, rushing for 211 yards on 35 carries. He rushed for four or more yards on 23 of his carries. Patterson also got into the act, lining up in the backfield in the power I formation and taking a handoff 33 yards for the first Vikings score. Cassel sparked the offense with 243 passing yards after replacing Ponder, who threw for just 40 yards in the first half. The Vikings generated some pressure against Bears quarterback Josh McCown, who was sacked four times, but the coverage beyond the second level was not good.

What went wrong: Bears wide receiver Alshon Jeffery beat Cook for an 80-yard touchdown and a 46-yard score before Cook was mercifully removed from the game after touching an official. Jeffery had a franchise-record 249 receiving yards, which partially explains why Brandon Marshall was held to just 45 by Rhodes and company. The Vikings could not stop the run either, as Matt Forte and the Bears rushed for 135 yards on 25 carries. Pass protection was an issue for the offense, as the Bears recorded five sacks, including two from Julius Peppers up the gut.

Turning point: The Vikings won in a long, crazy overtime period in which one Vikings field goal was taken off the board and Bears missed a potential game-winner on second down. But the Vikings never would have gotten to overtime had they not converted on fourth-and-long late in regulation. Standing in his end zone, Cassel made a tough throw to wide receiver Jerome Simpson. That 20-yard gain kept the Vikings alive and kick-started their game-tying drive.

X-factor: With size, speed, vision and lateral quickness, Peterson is the total package as he showed Sunday when he bullied through the Bears or jump-cut around them. Facing yet another stacked box on one fourth-down play, Peterson cut back to squeeze between a pair of Bears and spun out of two tackles for a 19-yard gain. It might take a Herculean effort for the Ravens to totally shut down Peterson, but if they do they should win easily at home.